1. Technical Field
The present invention relates to a touch panel, and more particularly, to a touch-sensing structure for a touch panel, and a touch-sensing method thereof.
2. Description of the Related Art
With development of the touch screen, nowadays, two kinds of touch-sensing structures for embedded touch screen are used widely, one of which is a passive touch-sensing structure, and the other one is an active touch-sensing structure. The two kinds of touch-sensing structures are respectively shown in FIG. 1 and FIG. 2.
FIG. 1 is a schematic view of a touch screen employing the passive touch-sensing structure. Referring to FIG. 1, the touch screen includes a data driver 110, a touch panel 120, and a touch signal processing circuit 130. The touch panel 120 includes a plurality of pixels; each pixel is consisted of a thin-film transistor (TFT), a storage capacitor Cst, and a pixel capacitor Clc. In addition, the touch panel 120 further includes a plurality of data lines 140, a plurality of gate lines 150, a plurality of common lines 160, a plurality of sensing units 170, a plurality of first touch-signal reading lines 180-1, and a plurality of second touch-signal reading lines 180-2. These sensing units 170 are used to detect a touch position corresponding to a touch action imposed in the touch panel by a user. Each sensing unit 170 is electrically coupled to the touch signal processing circuit 130 via one of the first touch-signal reading lines 180-1 and one of the second touch-signal reading lines 180-2, so as to enable the touch signal processing circuit 130 to obtain X-axis and Y-axis coordinates of the touch position according to the signals transmitted through the touch-signal reading lines 180-1 and 180-2.
It can be found from FIG. 1 that a sensing resolution of this kind of touch screen is determined by a distribution density of the sensing units 170 in the touch panel 120. However, as each of the sensing units 170 is electrically coupled to the touch signal processing circuit 130 via the touch-signal reading lines 180-1 and 180-2, and the distribution density of the sensing units 170 is usually limited by the channel number of the touch signal processing circuit 130, and thereby the sensing resolution of the touch screen is always low. If the manufacturer wants to ensure the sensing resolution of the touch screen, a more expensive touch signal processing circuit 130 with more channels has to be adopted. This may increase the cost of the touch screen.
Moreover, because each of the sensing units 170 is electrically coupled to the touch signal processing circuit 130 via the touch-signal reading lines 180-1 and 180-2, more external wires for the touch panel are needed with the increase of the distribution density of the sensing units 170, and accordingly a width of the edge portion (not shown) for the touch panel 120 should also be increased. Furthermore, another deficiency arises in this kind of passive touch-sensing structure, specifically, the touch-sensing structure can only perform a so-called single touch sensing.
FIG. 2 is a schematic view of a touch screen employing the active touch-sensing structure. Referring to FIG. 2, the touch screen includes a data driver 210, a touch panel 220, and a touch signal processing circuit 230. The touch panel 220 includes a plurality of pixels. Each pixel is also consisted of a thin-film transistor (TFT), a storage capacitor Cst, and a pixel capacitor Clc. In addition, the touch panel 220 further includes a plurality of data lines 240, a plurality of gate lines 250, a plurality of common lines 260, a plurality of sensing units 270, and a plurality of touch-signal reading lines 280. These sensing units 270 are also used to detect a touch position of a user in the touch panel. Each sensing unit 270 is electrically coupled to the touch signal processing circuit 230 via one of the touch-signal reading lines 280, so as to enable the touch signal processing circuit 230 to obtain X-axis and Y-axis coordinates of the touch position according to the signals transmitted through the touch-signal reading lines 280.
It can be found from FIG. 2 that a sensing resolution of this kind of touch screen is also determined by a distribution density of the sensing units 270 in the touch panel 220. As the distribution density of the sensing units 270 is usually limited by the channel number of the touch signal processing circuit 230, the sensing resolution of the touch screen is always low. If the manufacturer wants to ensure the sensing resolution of the touch screen, a more expensive touch signal processing circuit 230 with more channels has to be adopted. This may increase the cost of the touch screen. Moreover, because each of the sensing units 270 is electrically coupled to the touch signal processing circuit 230 via the touch-signal reading lines 280, more external wires for the touch panel are needed with the increase of the distribution density of the sensing units 270, and accordingly a width of the edge portion (not shown) for the touch panel 220 will also be increased.
Although this active touch-sensing structure can perform multi touch sensing, an aperture ratio of the pixel is reduced and thereby diminishing the light transmission rate of the pixel because the sensing units 270 in this structure are made up of TFTs. In addition, as the sensing units 270 in this structure are coupled to the gate lines 250, and operate accompanying with scanning rate of the gate lines, a touch response speed of the touch screen is low.
What is needed, therefore, is a touch-sensing structure that can overcome the above-described deficiencies. What is also needed is a touch-sensing method.